Understanding Our Sun

Age: Estimates calculate our sun is 4.6 billion years old, ands will continue burning its hydrogen fuel for another 5 billion years. Will it eventually burn out? Yes, of course — we all learned that in elementary school, right? For those fretting about the lifespan of their PV system’s power source, don’t worry.

Size: The sun is an average-sized star, we find at Cornell’s “Ask An Astronomer.” Here, Christopher Springob tells us, “The biggest stars are more than 100 times as massive as the Sun, and the smallest stars are less than 1/10th as massive as the Sun.”

Closeup Inspection: The NASA video below is worth seeing. In it, we learn that hydrogen is fused into helium in the core of the sun.

Solar History

Solar Ignitors: Historian John Perlin provides this information gem: During the sixth century BCE, Confucius wrote about the common use of curved mirrors shaped from shiny metal to concentrate the rays of the sun for making fire. These became known as yang­­-suis ­­– translating to solar ignitors or burning mirrors. According to the great philosopher, upon waking up, the eldest son would attach a solar ignitor to his belt as he dressed for the day. It was his duty to focus the solar rays onto kindling to start the family’s cooking fire.

Photovoltaics’ Discovery: Willoughby Smith’s 1872 experiments that proved the photosensitivity of selenium stirred keen interest in two British scientists, William Grylls Adams and Richard Evans Day, to discover something previously unknown to science – that a current could be started by the action of “light alone” in a solid-state material. The two scientists called the flow of electricity caused by light, “photoelectric.” Today, we say, “photovoltaic.” So began in 1875 the first stirrings of today’s solar revolution.

Solar Technology

Photovoltaics: Historian John Perlin said this about the public reaction to Einstein’s photoelectric discovery: “Even after proving the validity of Einstein’s light quanta equation in explaining the photoelectric effect, Milliken dismissed the physicality of the photon as ‘untenable.’ In 1923, 18 years after Einstein published his light quanta piece, American physicist Arthur Hailey Compton created a collision between a stationary electron and a short wave of light. Just as in billiards, when the cue ball strikes its target, the light wave transferred some of its energy and momentum to the electron… After the Compton Experiment, the reality of Einstein’s photon and the photovoltaic effect gained universal acceptance in the scientific community.”

Concentrated Solar Power: Concentrated solar power (also called concentrating solar power, concentrated solar thermal, and CSP) systems generate solar power by using mirrors or lenses to concentrate a large area of sunlight, or solar thermal energy, onto a small area. The heat is what is used to eventually spin a turbine and generate electricity (very different from how solar PV generates electricity).

Solar Net Metering: The world’s first net-metered solar system was connected to the grid in 1979, when 28-year old architect Steven Strong put solar PV panels on two buildings making up a 270-unit apartment complex and connected them to a utility meter that tracked how much solar electricity was sent back into the grid. “A small meter mounted on the wall of the dining room told the story in kilowatts. When the utility power was drawn it ran forward. But when the PV was pumping out excess power, it ran backward.”

Solar Metrics

Solar Power In The US:Solar power in the United States surpassed 20 gigawatts (GW) of installed capacity in 2015. “The report also highlights the fact that 40% of all new electric generating capacity brought online in the first half of 2015 in the US came from solar. 21 states throughout the country now have more than 100 MW of solar PV capacity, though the top five states in terms of solar capacity account for nearly ¾ of the total US cumulative PV capacity.”

Solar US Growth Spurt: From 2006 to 2013, the number of homes with solar power grew by more than 1,000 percent in the US, from 30,000 home to 400,000 homes.

Cost Of Solar: The lowest electricity price ever bid by a solar developer was 0.1875 Riyals ($0.049) per kilowatt-hour (kWh) by the Saudi Electric Company in Saudi Arabia in August 2015. That’s far less than the average price of electricity from natural gas or any other electricity source in the region.

There is plenty more that can be added to this list, but I hope this is a great starting place for understanding this stunning renewable energy source.